Improved nanoparticle productivity via flat-top 49-beam nanosecond pulsed laser ablation in liquids.

Pulsed laser ablation in liquids (PLAL) is a versatile and environmentally friendly technique for producing surfactant-free, high-purity nanoparticles (NPs) suitable for applications in catalysis and biomedicine. However, its industrial scalability is limited by low throughput and the high cost of high-power ultrafast (ps/fs) laser systems typically required to achieve efficient NP production. Here, we demonstrate a cost-effective high-throughput PLAL approach using a high-power nanosecond laser (500 W) combined with a diffractive optical element (DOE) that splits each pulse into 49 identical sub-beams. This multi-beam configuration enables operation at optimal fluences and spot interpulse distances,, which may contribute to reducing shielding effects and improving the ablation efficiency. Using gold as a model material, we achieve a NP productivity of ~ 3.3 g h⁻¹. Notably, the investment-specific productivity reaches 13.2 mg (h·k€)⁻¹, exceeding that of ultrafast laser-based systems and demonstrating superior economic efficiency without compromising NP size. Possible shielding factors such as cavitation bubble dynamics, persistent bubbles, and NP accumulation in the beam path are discussed to identify optimal ablation conditions. These findings provide important insights into PLAL upscaling and establish multi-beam ns PLAL as a promising route for high-throughput NP production. CLINICAL TRIAL REGISTRATION: Not applicable.